Harvesting a worm bin involves separating worms from the earthen compost that they create which is known as vermapost. Vermapost is the result of allowing worms to gather in a compost bin and feed off of the waste materials that you fill the compost bin with. Knowing when to harvest the worm bin will help you know when to remove the worms in order to gain access to the vermapost.
Step 1 - What Vermapost Looks Like
The vermapost will look like soil that has shredded paper in it or like vegetable scraps. To create this look, stop feeding the worms for 1 to 2 weeks and that should make the vermapost ready for harvesting.
Step 2 - Deciding Where to Work
Move the bin to a porch or an area in the yard that is easier to work in. The bin should be taken out of the sun to prevent the worms from getting overheated. Use a bucket and a second bin to sort the worms, using the bucket to place the worms and worm eggs in and the second bin for the vermapost. The worm eggs are easy to identify because they look like small yellow seeds. Take care when sorting through the vermapost in order to protect the worms and their eggs.
Step 3 - Use Light to Move the Worms Downward
If you decide to work indoors as opposed to leaving the bins outside, use a clip light and attach it to the compost bin. Shining the light into the bin will cause the worms to bury themselves toward the bottom of the bin in order to avoid the light. This will make it easier to separate the top level of the vermapost first before you get to the worms that have moved to the bottom. Working outside will not require the use of the light if it is bright enough outside.
Step 4 - Working with the Lumps of Vermapost
As you work through the piles of vermapost, carefully brush the lumps in order to expose any worms or worm eggs that are inside. Place the worms and worm eggs into the bucket and the vermapost into the second bin.
Step 5 - Work at a Moderate Pace
As you remove layers of vermapost, the worms will continue to move toward the bottom of the vermapost bin. As you continue to work through the layers, you may find that you have more worms than vermapost. If this happens, stop for a while and keep the light on the bin so that the worms can continue working to the bottom of the bin.
Step 6 - Refilling the Bin
After you remove all of the vermapost and place it in the second bin and have placed all of the worms in the bucket, fill the bin 1/2 full with potting soil. Place the worms back into the bin and continue with the composting process. Worms eat about half their weight so you will need to revisit this process again in about 3 months or so.